Although wind-blown dunes composed of carbonate sand are widespread along subtropical shorelines, such dune deposits were, until very recently, unknown from strata more than several million years old. Discovery of eolian limestones of Pennsylvanian age in southwestern U.S. supports the view that the origin of carbonate-rich dunes is related to the shoreline fluctuations that accompany glacial epochs. I will conduct detailed field and laboratory study of eolian limestones of southeastern Utah and of the Grand Canyon region of northern Arizona and southern Nevada. Outcrop and subsurface studies will determine the lateral extent of individual eolian limestone beds and document the vertical and lateral relationships of eolian and marine facies. Laboratory work will reconstruct the original texture and mineralogy of the dune sands as well as the processes and products of their subsequent alteration. The study will established improved criteria for the identification of ancient eolian limestones and will test several hypotheses for their origin. One of these hypotheses addresses the possibility that the incompleteness of many stratal sequences is due to wind erosion. Although eolian limestones represent a minor portion of the stratigraphic record, results of this study will be applicable to other sedimentary facies deposited during periods of Earth history characterized by rapid shoreline migration.
